package com.summli.basic.class04;


import java.util.Arrays;
import java.util.PriorityQueue;

/**
 * 堆排序：时间复杂度位n*logN 额外的空间复杂度位O(1)
 */
public class Code04_HeapSort {

    public static void heapSort(int[] arr) {
        if(arr == null || arr.length<2){
            return;
        }
        //对于已经给顶arr，首先新城大根堆的结构 时间复杂度位O（n*logn）
        for (int i = 0; i < arr.length; i++) {
            heapInsert(arr,i);
        }
        int size = arr.length;
        swap(arr,0,--size);
        while(size>0){
            heapify(arr,0,size);//时间复杂度为0(logn )
            swap(arr,0,--size);
        }
    }

    private static void heapify(int[] arr, int index, int size) {
        int left = 2*index+1;
        while(left<size){
            int lager = (left+1)<size && arr[left+1]>arr[left]?left+1:left;
            lager = arr[index]>arr[lager]?index:lager;
            if(lager == index){
                break;
            }
            swap(arr,index,lager);
            index = lager;
            left = 2*index +1;
        }
    }

    // 单次的时间复杂度位O（logN）
    private static void heapInsert(int[] arr, int index) {
        while(arr[index] > arr[(index-1)/2]){
            swap(arr,index,(index-1)/2);
            index = (index-1)/2;
        }
    }

    private static void swap(int[] arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
    // for test
    public static void comparator(int[] arr) {
        Arrays.sort(arr);
    }

    // for test
    public static int[] generateRandomArray(int maxSize, int maxValue) {
        int[] arr = new int[(int) ((maxSize + 1) * Math.random())];
        for (int i = 0; i < arr.length; i++) {
            arr[i] = (int) ((maxValue + 1) * Math.random()) - (int) (maxValue * Math.random());
        }
        return arr;
    }

    // for test
    public static int[] copyArray(int[] arr) {
        if (arr == null) {
            return null;
        }
        int[] res = new int[arr.length];
        for (int i = 0; i < arr.length; i++) {
            res[i] = arr[i];
        }
        return res;
    }

    // for test
    public static boolean isEqual(int[] arr1, int[] arr2) {
        if ((arr1 == null && arr2 != null) || (arr1 != null && arr2 == null)) {
            return false;
        }
        if (arr1 == null && arr2 == null) {
            return true;
        }
        if (arr1.length != arr2.length) {
            return false;
        }
        for (int i = 0; i < arr1.length; i++) {
            if (arr1[i] != arr2[i]) {
                return false;
            }
        }
        return true;
    }

    // for test
    public static void printArray(int[] arr) {
        if (arr == null) {
            return;
        }
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }

    // for test
    public static void main(String[] args) {
        System.out.println((0-1)/2);
        int testTime = 500000;
        int maxSize = 100;
        int maxValue = 100;
        boolean succeed = true;
        for (int i = 0; i < testTime; i++) {
            int[] arr1 = generateRandomArray(maxSize, maxValue);
            int[] arr2 = copyArray(arr1);
            heapSort(arr1);
            comparator(arr2);
            if (!isEqual(arr1, arr2)) {
                printArray(arr1);
                succeed = false;
                break;
            }
        }
        System.out.println(succeed ? "Nice!" : "Fucking fucked!");
    }

}
